Jack-screw.



E. M. BURNEY.

- Patented D60. 27, 1910.

n v 1AM. 4! m1 drawin s running a cf EDWARD M. BURNEY, OF CHICAGO, ILLINOIS.

JACK-SCREW.

Specification of Letters Patent.

Patented Dec. 27, 1910.

Application filed June 1, 1909. Serial No. 499,382.

To all whom it may concern:

Be it known that I, EDWARD M. BURNEY, a citizen of the United States, residing at Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Jack-Screws, of which the following is a specification.

My invention relates to jack screws, and the object of my invention is to provide an improved jack screw wherein. the screw and the cap pivot shall. be securely fixed to the head, to the end that the same shall be strong and durable and without liability of separation of the parts when in use.

A further object of my invention is to provide a device of the class mentioned which shall be of simple construction and which may be manufactured at low cost.

Other objects will appear hereinafter.

My invention will be more readily understood by reference. to...the.....accoiiipanying' .tion and in which- Figure l is an elevation of a jack screw, embodying my inventlon in its preferred form, Fig. 2 is a vertical sectional view of the same, the screw and cap pivot being shown in elevation, and Fig. 8 is a detail transverse section taken on substantially the line wm of Fig. 2.

Referring now to the drawings 1 indicates a screw having the usual thread 2. I extend the thread of the screw almost to the up er end thereof and terminate the same with a shoulder 3, the purpose of whichwill appear hereinafter.

4: indicates a cylindrical cap pivot having a peripheral annular groove 5 formed therein adJa-cent its lower end, and 6 the head of the screw. The head 6 is cast on the B d on, and provided with lever bar openings,

screw and pivot, the metal thereof extending several threads downwardly on the screw and above the groove 5 of the cap pivot. By constructing the screw in this manner separation of the several parts is prevented as the metal. of the head enters between the threads 2 and into the groove 5. The shoulder 3 at the upper end of the thread is also embedded in the metal of the head and prevents relative turning of the head and screw when the device is in use. The head is provided with radial lever bar openings 7 which are cored therein when the head is molded, and extend through the head between the ends of the screw and the pivot fl.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. A jack screw comprising a screw having a thread extending almost to its upper end and 'terminating- 't'n'pon "tifeurp ng several threads downwardly theresubstantially as described.

2. In a jack screw a head and a cylindrical cap pivot having a peripheral annular groove adjacent. its lower end, said lower end including said groove being embedded within said head when the latter is cast, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWARD M. BURNEY.

Witnesses:

JOSHUA R. H. PoTTs, HELEN F. LILLIS. 

